In recovering wave energy from a body of water, many impulse type devices (energy absorbers) have been proposed. The general structure of an impulse type device used to capture wave energy discussed herein typically has a panel attached to a lever arm with a hinged connection to make rotation possible. Some devices have an inverted structure similar to a pendulum formed with a hinged end of the panel or lever arm, while others have the hinges in a vertical plane (a sideways pendulum). These panels are hinged to a shore-supported structure above the sea surface while the panel is extended into the wave profile. Examples of impulse-type “wave motor” devices are described in U.S. Pat. No. 918,870 to Lawrence, U.S. Pat. No. 1,073,682 to Henderson, U.S. Pat. No. 4,170,738 to Smith, and U.S. Pat. No. 4,371,788 also to Smith. However, while the prior art devices are designed to produce long traverse motion (stroke) for energy conversion, they do not produce the high pressures that might be necessary for efficient desalination and other high pressure uses.
Desalination of seawater for potable, irrigation, and other consumption uses is often required in remote regions that lack an electrical power infrastructure or where fuel supply is expensive and difficult to maintain. It is highly desirable to provide desalination of seawater powered by a renewable energy source in such locations. Some proposals have been made to use the power of waves to drive an evaporator-condenser cycle for desalination, such as disclosed in U.S. Pat. No. 4,555,307 to Hagen, or to drive an electric generator for desalination, such as disclosed in U.S. Pat. No. 4,672,222 to Ames. Another proposal has been to use wave energy to drive a DC generator which then drives a high pressure pump to desalinate seawater through reverse osmosis, such as disclosed in U.S. Pat. No. 5,167,786 to Eberle. Another proposal employs wave energy to drive a high pressure pump to produce an output steam of pressurized water which can be used in an external converter to desalinate seawater through reverse osmosis, such as disclosed in U.S. Pat. No. 5,842,838 to Berg. However, by employing successively staged energy conversion steps, these systems tend to operate at low efficiencies and have difficulty maintaining operation despite tidal variations.